Referring to FIG. 1A, a nacelle 100 of an aircraft may be used to house an engine. The nacelle 100 may be composed of multiple components, such as for example a thrust reverser 102. The thrust reverser 102 includes components that are used to generate reverse thrust during aircraft descent/landing.
FIG. 1B illustrates a portion of a conventional nacelle 100/thrust reverser 102 used to generate reverse thrust. A bypass duct 154 is at least partially defined between a (radially outer portion of an) inner fixed structure (IFS) 158 and a (radially inner portion of a) cowl/sleeve 162.
After aircraft landing the thrust reverser 102 is in a deployed state. In the deployed state, blocker doors (one of which is shown in FIG. 1B as reference character 166) assume a deployed position as shown in FIG. 1B, where the blocker doors 166 redirect substantially all of a bypass airflow flowing through the bypass duct 154 radially outboard through one or more sets of cascades 170. When the thrust reverser 102 is in the deployed state, the sleeve 162 is translated aft to expose the cascades 170 to the external environment and to avoid having the bypass flow impinge on a radially inner surface of the sleeve 162. For completeness, a link 174 is shown that couples a blocker door 166 to the IFS 158.
When the aircraft is in flight/cruise the thrust reverser 102 is in a stowed state. Relative to what is shown in FIG. 1B, when the thrust reverser 102 is in the stowed state the sleeve 162 is translated forward and the blocker doors 166 assume a stowed position denoted by reference character 178. In the stowed state, the cascades 170 are concealed from the bypass duct 154 at least in part by the blocker doors 166 and the cascades are concealed from the external environment by the sleeve 162.
When the blocker doors 166 are in the stowed position 178, a radially inner surface 166a of a blocker door 166 interfaces with the bypass duct 154. This means that there are numerous steps and gaps that contribute to losses/inefficiencies during aircraft flight/cruise. These steps/gaps also reduce the area that can be acoustically treated for noise reduction. Furthermore, the cascades 170 are typically fixed (e.g., do not translate), dictating to an extent the length of the sleeve 162 that must be used.